scholarly journals Numerical Simulation of Deformation Band Occurrence and the Associated Stress Field during the Growth of a Fault-Propagation Fold

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 257
Author(s):  
Romain Robert ◽  
Pauline Souloumiac ◽  
Philippe Robion ◽  
Christian David
Keyword(s):  
Numerical Simulations ◽  
Deformation Band ◽  
Early Stage ◽  
Shear Bands ◽  
Burial History ◽  
Deformation Bands ◽  
Fault Propagation ◽  
Compaction Bands ◽  
South Central ◽  
Fault Propagation Fold

Knowledge of the paleo-stress distribution is crucial to understand the fracture set up and orientations during the tectonic evolution of a basin, and thus the corresponding fluid flow patterns in a reservoir. This study aims to predict the main stress orientations and evolution during the growth of a fold by using the limit analysis method. Fourteen different steps have been integrated as 2D cross sections from an early stage to an evolved stage of a schematic and balanced propagation fold. The stress evolution was followed during the time and burial of syn tectonic layers localized in front of the thrust. Numerical simulations were used to predict the occurrence and orientation of deformation bands, i.e., compaction and shear bands, by following the kinematic of a fault-propagation fold. The case study of the Sant-Corneli-Boixols anticline was selected, located in the South Central Pyrenees in the Tremp basin, to constrain the dimension of the starting models (or prototypes) used in our numerical simulations. The predictions of the numerical simulations were compared to field observations of an early occurrence of both pure compaction- and shear-enhanced compaction bands in the syn-tectonic Aren formation located in front of the fold, which are subjected to early layer parallel shortening during the burial history. Stress magnitude and stress ratio variations define the type of deformation band produced. Our results show that the band occurrence depends on the yield envelope of the host material and that a small yield envelope is required for these shallow depths, which can only be explained by the heterogeneity of the host rock facies. In our case, the heterogeneity can be explained by a significant contribution of carbonate bioclasts in the calcarenite rock, which change the mechanical behavior of the whole rock.

scholarly journals Distribution, microphysical properties, and tectonic controls of deformation bands in the Miocene subduction wedge (Whakataki Formation) of the Hikurangi subduction zone

Solid Earth ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 141-170
Author(s):  
Kathryn E. Elphick ◽  
Craig R. Sloss ◽  
Klaus Regenauer-Lieb ◽  
Christoph E. Schrank
Keyword(s):  
Microstructural Analysis ◽  
Shear Bands ◽  
Normal Faults ◽  
Pore Collapse ◽  
Deformation Bands ◽  
Progressive Deformation ◽  
Compaction Bands ◽  
Microphysical Properties ◽  
Sealing Capacity ◽  
Grain Crushing

Abstract. We analyse deformation bands related to horizontal contraction with an intermittent period of horizontal extension in Miocene turbidites of the Whakataki Formation south of Castlepoint, Wairarapa, North Island, New Zealand. In the Whakataki Formation, three sets of cataclastic deformation bands are identified: (1) normal-sense compactional shear bands (CSBs), (2) reverse-sense CSBs, and (3) reverse-sense shear-enhanced compaction bands (SECBs). During extension, CSBs are associated with normal faults. When propagating through clay-rich interbeds, extensional bands are characterised by clay smear and grain size reduction. During contraction, sandstone-dominated sequences host SECBs, and rare CSBs, that are generally distributed in pervasive patterns. A quantitative spacing analysis shows that most outcrops are characterised by mixed spatial distributions of deformation bands, interpreted as a consequence of overprint due to progressive deformation or distinct multiple generations of deformation bands from different deformation phases. As many deformation bands are parallel to adjacent juvenile normal faults and reverse faults, bands are likely precursors to faults. With progressive deformation, the linkage of distributed deformation bands across sedimentary beds occurs to form through-going faults. During this process, bands associated with the wall-, tip-, and interaction-damage zones overprint earlier distributions resulting in complex spatial patterns. Regularly spaced bands are pervasively distributed when far away from faults. Microstructural analysis shows that all deformation bands form by inelastic pore collapse and grain crushing with an absolute reduction in porosity relative to the host rock between 5 % and 14 %. Hence, deformation bands likely act as fluid flow barriers. Faults and their associated damage zones exhibit a spacing of 9 m on the scale of 10 km and are more commonly observed in areas characterised by higher mudstone-to-sandstone ratios. As a result, extensive clay smear is common in these faults, enhancing the sealing capacity of faults. Therefore, the formation of deformation bands and faults leads to progressive flow compartmentalisation from the scale of 9 m down to about 10 cm – the typical spacing of distributed, regularly spaced deformation bands.

Physical and chemical strain-hardening during faulting in poorly lithified sandstone: The role of kinematic stress field and selective cementation

2019 ◽  
Vol 132 (5-6) ◽  
pp. 1183-1200 ◽  
Author(s):  
Mattia Pizzati ◽  
Fabrizio Balsamo ◽  
Fabrizio Storti ◽  
Paola Iacumin
Keyword(s):  
Stress Field ◽  
Strain Hardening ◽  
Fault Zone ◽  
Deformation Band ◽  
Early Stage ◽  
Damage Zone ◽  
Isotope Analysis ◽  
Deformation Bands ◽  
Multidisciplinary Study ◽  
Diagenetic Evolution

Abstract In this work, we report the results of a multidisciplinary study describing the structural architecture and diagenetic evolution of the Rocca di Neto extensional fault zone developed in poorly lithified sandstones of the Crotone Basin, Southern Italy. The studied fault zone has an estimated displacement of ∼90 m and consists of: (1) a low-deformation zone with subsidiary faults and widely spaced deformation bands; (2) an ∼10-m-wide damage zone, characterized by a dense network of conjugate deformation bands; (3) an ∼3-m-wide mixed zone produced by tectonic mixing of sediments with different grain size; (4) an ∼1-m-wide fault core with bedding transposed into foliation and ultra-comminute black gouge layers. Microstructural investigations indicate that particulate flow was the dominant early-stage deformation mechanism, while cataclasis became predominant after porosity loss, shallow burial, and selective calcite cementation. The combination of tectonic compaction and preferential cementation led to a strain-hardening behavior inducing the formation of “inclined conjugate deformation band sets” inside the damage zone, caused by the kinematic stress field associated with fault activity. Conversely, conjugate deformation band sets with a vertical bisector formed outside the damage zone in response to the regional extensional stress field. Stable isotope analysis helped in constraining the diagenetic environment of deformation, which is characterized by mixed marine-meteoric signature for cements hosted inside the damage zone, while it progressively becomes more meteoric moving outside the fault zone. This evidence supports the outward propagation of fault-related deformation structures in the footwall damage zone.

A kinematic trishear model to predict deformation bands in a fault-propagation fold, East Kaibab monocline, Utah

AAPG Bulletin ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 109-132 ◽  
Author(s):  
J. P. Brandenburg ◽  
Faruk Omer Alpak ◽  
John G. Solum ◽  
Steve J. Naruk
Keyword(s):  
Deformation Bands ◽  
Fault Propagation ◽  
Fault Propagation Fold

The effect of deformation bands on simulated fluid flow within fault-propagation fold trap types: Lessons from the San Rafael monocline, Utah

AAPG Bulletin ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 1523-1540 ◽  
Author(s):  
Luisa F. Zuluaga ◽  
Atle Rotevatn ◽  
Eirik Keilegavlen ◽  
Haakon Fossen
Keyword(s):  
Fluid Flow ◽  
Deformation Bands ◽  
Fault Propagation ◽  
Fault Propagation Fold ◽  
San Rafael

scholarly journals Distribution, microphysical properties, and tectonic control of deformation bands in the Miocene accretionary prism (Whakataki Formation) of the Hikurangi subduction zone

2020 ◽  
Author(s):  
Kathryn E. Elphick ◽  
Craig R. Sloss ◽  
Klaus Regenauer-Lieb ◽  
Christoph E. Schrank
Keyword(s):  
Microstructural Analysis ◽  
Shear Bands ◽  
Accretionary Prism ◽  
Normal Faults ◽  
Pore Collapse ◽  
Deformation Bands ◽  
Progressive Deformation ◽  
Compaction Bands ◽  
Grain Crushing ◽  
Normal Sense

Abstract. We analyse deformation bands related to both horizontal contraction and horizontal extension in Miocene turbidites of the Whakataki Formation south of Castlepoint, Wairarapa, North Island, New Zealand. In the Whakataki Formation, four sets of cataclastic deformation bands are identified: (1) normal-sense Compactional Shear Bands (CSBs); (2) normal-sense Shear-Enhanced Compaction Bands (SECBs); (3) reverse-sense CSBs; and (4) reverse-sense SECBs. During extension, CSBs form most frequently with rare SECBs. Extensional CSBs are often, but not exclusively, associated with normal faults. During contraction, distributed SECBs are observed most commonly, sometimes clustering around small reverse faults and thrusts. Contractional CSBs are primarily found in the damage zones of reverse faults. The quantitative spacing analysis shows that most outcrops are characterised by mixed spatial distributions of deformation bands, interpreted as a consequence of overprint due to progressive deformation or distinct multiple generations of deformation bands from different deformation phases. Since many deformation bands are parallel to adjacent juvenile normal- and reverse-faults, bands are likely precursors to faults. With progressive deformation, the linkage of distributed deformation bands across sedimentary beds occurs to form through-going faults. During this process, bands associated with the wall-, tip-, and interaction damage zones overprint earlier distributions resulting in complex spatial patterns. Regularly spaced bands are pervasively distributed when far away from faults. Microstructural analysis shows that all deformation bands form by inelastic pore collapse and grain crushing with an absolute reduction in porosity relative to the host rock between 5 and 14 %. Hence, deformation bands likely act as fluid flow barriers. Faults and their associated damage zones exhibit a spacing of order ten metres on the scale of 10 km and are more commonly observed in areas characterised by higher mudstone to sandstone ratios. As a result, extensive clay smear is common in these faults, enhancing the sealing capacity of faults. Therefore, the formation of deformation bands and faults leads to progressive flow compartmentalisation from the scale of ten metres down to about ten centimetres, the typical spacing of distributed deformation bands.

Structural deformation-metamorphism and exhumation processes of Yuanmou metamorphic complex, Yunnan, China

2021 ◽  
Author(s):  
Xuemei Cheng ◽  
Shuyun Cao
Keyword(s):  
High Temperature ◽  
Electron Backscatter Diffraction ◽  
Early Stage ◽  
Structural Features ◽  
Detachment Fault ◽  
Ductile Deformation ◽  
Structural Deformation ◽  
Subsequent Stage ◽  
Metamorphic Complex ◽  
South Central

<p>Within orogenic zone and continental extensional area, it often developed metamorphic complex or metamorphic gneiss dome that widely exposed continental mid-lower crustal rocks, which is an ideal place to study exhumation processes of deep-seated metamorphic complex and rheology. The Yuanmou metamorphic complex is located in the south-central part of the "Kangdian Axis" in the western margin of Qiangtang Block and Yangtze Block, which is a part of the anticline of the Sichuan-Yunnan platform. Many research works mainly focus on the discussion of intrusion ages, aeromagnetic anomalies, and polymetallic deposits. However, the exhumation process and mechanism of the Yuanmou metamorphic complex are rarely discussed and still unclear. This study, based on detailed field geological observations, optical microscopy (OM), cathodoluminescence (CL), electron backscatter diffraction (EBSD) and electron probe (EMPA) were performed to illustrate the geological structure features, deformation-metamorphic evolution process and its tectonic significance of Yuanmou metamorphic complex during the exhumation process. All these analysis results indicate that the Yuanmou metamorphic complex generally exhibits a dome structure with deep metamorphic rocks and deformed rocks of varying degrees widely developed. Mylonitic gneiss and granitic intrusions are located in the footwall of the Yuanmou, which have suffered high-temperature shearing. The mylonitic fabrics and mineral stretching lineations in the deformed rock are strongly developed, forming typical S-L or L-shaped structural features. The high-temperature ductile deformation-metamorphism environment is high amphibolite facies, that is, the temperature range is between 620 ~ 690 ℃ and the pressure is between 0.8 ~ 0.95 Gpa. In the deformed rocks closed to the detachment fault, some of the mylonite fabric features are retained, but most of them have experienced a strongly overprinted retrogression metamorphism and deformation. At the top of the detachment fault zone, it is mainly composed of cataclasites and fault gouge. The comprehensive macro- and microstructural characteristics, geometry, kinematics, and mineral (amphibole, quartz and calcite) EBSD textures indicate that the Yuanmou metamorphic complex has undergone a progressive exhumation process during regional extension, obvious high-temperature plastic deformation-metamorphism in the early stage, and superimposed of low-temperature plastic-brittle and brittle deformation in the subsequent stage, which is also accompanied by strong fluid activities during the exhumation process.</p>

scholarly journals PENGARUH PENINGKATAN DERAJAT DEFORMASI CANAI HANGAT TERHADAP KARAKTERISTIK DEFORMATION BAND PADUAN Cu-Zn 70/30

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Eka Febriyanti ◽  
Dedi Priadi ◽  
Rini Riastuti
Keyword(s):  
Deformation Band ◽  
Cold Working ◽  
Testing Machine ◽  
Deformation Bands ◽  
Double Pass ◽  
Deformation Degree ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Hot Rolled ◽  
Zn Alloy

Cu-Zn 70/30 alloy has properties that is relatively soft, ductile, and easy to perform by cold working. However, cold working has the disadvantage that require equipment which has higher loading capacity to generate strength and higher density thus increasing of machining cost. In addition, strain hardening phenomenon due to cold working process resulted in decreasing of ductility material. Therefore, it is necessary alternative fabrication processes to optimize the mechanical properties of Cu-Zn alloy 70/30 that with the TMCP method. TMCP is metal forming material by providing large and controlled plastic strain to the material. TMCP using the deformation percentage variation that 32.25%, 35.48%, and 38.7% from hot rolled research at 500°C temperature in double pass reversible which performed on Cu-Zn 70/30 plate. By tensile testing using universal testing machine can be seen that the Cu-Zn 70/30 alloy on 32.25% degree of deformation, both of UTS and YS respectively are 505 MPa and 460 MPa. Whereas from examination of thickness and density deformation bands by FE-SEM shows denser and thicker deformation band proportional with increasing of deformation degree.Moreover, the values of tensile strength at the edge of the area and the center is directly proportional to the density and thickness of the deformation band.AbstrakPaduan Cu-Zn 70/30 memiliki sifat yang relatif lunak, ulet, dan mudah dilakukan pengerjaan dingin. Namun, pengerjaan dingin memiliki kekurangan yaitu membutuhkan peralatan yang memiliki kapasitas pembebanan tinggi untuk menghasilkan kekuatan dan kepadatan tinggi sehingga meningkatkan biaya permesinan. Selain itu, fenomena pengerasan regang akibat proses pengerjaan dingin menghasilkan penurunan keuletan material. Oleh karena itu, diperlukan alternatif proses fabrikasi untuk mengoptimalkan sifat mekanik paduan Cu-Zn 70/30 salah satunya dengan metode TMCP. TMCP merupakan suatu proses perubahan bentuk suatu material dengan cara memberikan regangan plastis yang besar dan terkontrol terhadap material. TMCP dengan menggunakan variasi persentase deformasi sebanyak 32,25%, 35,48%, dan 38,70% dari penelitian canai hangat di suhu 500oC secara double pass reversible dilakukan pada pelat paduan Cu-Zn 70/30. Dengan melakukan pengujian tarik menggunakan mesin uji tarik universal testing machine dapat dilihat bahwa pada material paduan Cu-Zn 70/30 pada derajat deformasi 32,25% menghasilkan nilai UTS dan YS masing-masing sebesar 505 MPa dan 460 MPa. Sedangkan dari hasil pengamatan ketebalan dan kerapatan deformation band menggunakan FE-SEM menunjukkan deformation band yang lebih rapat dan lebih tebal sebanding dengan semakin meningkatnya derajat deformasi. Selain itu, nilai kekuatan tarik pada daerah tepi dan tengah berbanding lurus dengan kerapatan dan ketebalan deformation band.Keywords: 70/30 Cu-Zn alloy, warm rolled, deformation degree, deformation bands

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